Apple's Passbook gained compatibility with two major apps on Tuesday as British Airways updated its boarding pass and travel title to support the coupon and pass management service, while Subway added integration for customers in the UK.

Six months after receiving approval from the FAA to test of iPads as replacements for traditional paper flight charts, American Airlines is set to be the first major commercial carrier to use Apple's device in all phases of flight.

Delta Airlines has started testing iPads as electronic flight bags domestically, in order to evaluate the viability of replacing printed on-board manuals and other information with digital versions and custom iOS applications.

The U.S. Federal Aviation Administration has authorized a smattering of commercial and charter airlines to replace cumbersome 40-pound paper manuals with iPads, which will instead serve as so-called electronic flight bags for pilots.

American Airlines has started a pilot program to test the use of Apple's iPad running a specialized app providing paperless flight navigation charts, a tool it says will save it over a million dollars a year in fuel costs.

With the Federal Aviation Administration granting early approval for the use of the iPad in airplane cockpits, major commercial airline companies like Delta are exploring the possibility of using Apple's touchscreen tablet to ditch paper maps entirely.